Dissertations and Theses - Physics
http://hdl.handle.net/2142/8859
Dissertations in PhysicsSun, 07 Feb 2016 15:14:38 GMT2016-02-07T15:14:38ZCellular influence on protein folding
http://hdl.handle.net/2142/88268
Cellular influence on protein folding
Gelman, Hannah Madeline
Advances in the study of protein folding and structure have greatly expanded our understanding and ability to predict and modify protein structure and, increasingly, even function. Attention has now turned to developing a better understanding of how protein structure, function, and folding interact to enable necessary biochemical processes in the cell. This work includes efforts to better understand the folding of model proteins in vitro, with an eye towards how this insight can inform questions about protein dynamics in more complex environments and protein-protein interactions. In addition, recent advances in NMR, mass spectrometry, fluorescence microscopy, and other techniques have enabled the study of protein folding in the cellular environment and have shown that the effect of the cell on protein folding is variable and difficult to predict. Researchers continue to develop new tools to investigate the effect of the cellular environment on more complicated biomolecular systems.
This thesis is roughly divided into two sections: Chapters 1-2 discuss fast protein folding in vitro and Chapters 3-6 address the study of protein folding and folding mediated processes in the cell. Chapter 1 is a survey of the theory of protein folding and the major techniques and findings from the study of fast folding proteins in vitro, with a special emphasis on how this work informs our understanding of more complex protein dynamics. Chapter 2 characterizes dodine, a compound that combines the properties of chatropic denaturants and detergents.
Chapter 3 is an introduction to how perturbative methods developed in vitro can be applied to study processes in the cell that are inaccessible by conventional steady-state measurements. Chapter 4 is a practical guide to improving the accuracy and reliability of Fluorescence Relaxation Imaging (FReI), our Fӧrster Resonance Energy Transfer (FRET) microscopy based technique for studying biomolecular kinetics in the cell. Chapter 5 describes the development and characterization of the fluorescent construct GPGK-tc and its use to study population-level variation of protein folding in E. coli. Finally, Chapter 6 examines the interaction of the chaperone Hsp70 with an unfolding substrate using a FRET-based binding assay both in vitro and in cells.
fluorescence microscopy; protein folding; biophysics; chaperones; Fӧrster Resonance Energy Transfer (FRET)
Tue, 14 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/882682015-07-14T00:00:00ZGelman, Hannah MadelineNon-equilibrium dynamics of ultracold atoms in optical lattices
http://hdl.handle.net/2142/88077
Non-equilibrium dynamics of ultracold atoms in optical lattices
Chen, David
This thesis describes experiments focused on investigating out-of-equilibrium phenomena in the Bose-Hubbard Model and exploring novel cooling techniques for ultracold gases in optical lattices.
In the first experiment, we study quenches across the Mott-insulator-to-superfluid quantum phase transition in the 3D Bose-Hubbard Model. The quench is accomplished by continuously tuning the ratio of the Hubbard energies. We observe that the degree of excitation is proportional to the fraction of atoms that cross the phase boundary, and that the amount of excitations and energy produced during the quench have a power-law dependence on the quench rate. These phenomena suggest an excitation process analogous to the mechanism for defect generation in non-equilibrium classical phase transitions. This experiment constitutes the first observation of the Kibble-Zurek mechanism in a quantum quench. We have reported our findings in Ref. [1].
In a second experiment, published in Ref. [2], we investigate dissipation as a method for cooling a strongly interacting gas. We introduce dissipation via a bosonic reservoir to a strongly interacting bosonic gas in the Mott-insulator regime of a 3D spin-dependent optical lattice. The lattice atoms are excited to a higher energy band using laser-induced Bragg transitions. A weakly interacting superfluid comprised of atoms in a state that does not experience the lattice potential acts as a dissipative bath that interacts with the lattice atoms through collisions. We measure the resulting bath-induced decay using the atomic quasimomentum distribution, and we compare the decay rate with predictions from a weakly interacting model with no free parameters. A competing intrinsic decay mechanism arising from collisions between lattice atoms is also investigated. The presence of intrinsic decay can not be accommodated within a non-interacting framework and signals that strong interactions may play a central role in the lattice-atom dynamics. The intrinsic decay process we observe may negatively impact the success of cooling via dissipation because a fraction of intrinsic decay events can deposit a large amount of energy into the lattice gas.
In a third experiment, we develop and carry out the first demonstration of cooling an atomic quasimomentum distribution. Our scheme, applied in a proof-of-principle experiment to 3D Bose-Hubbard gas in the superfluid regime, involves quasimomentum-selective Raman transitions. This experiment is motivated by the search of new cooling techniques for lattice-trapped gases. Efficient cooling exceeding heating rates is achieved by iteratively removing high quasimomentum atoms from the lattice. Quasimomentum equilibration, which is necessary for cooling, is investigated by directly measuring rethermalization rates after bringing the quasimomentum distribution of the gas out of equilibrium. The measured relaxation rate is consistent at high lattice depths with a short-range, two-particle scattering model without free parameters, despite an apparent violation of the Mott-Ioffe-Regel bound. Our results may have implications for models of unusual transport phenomena in materials with strong interactions, such as heavy fermion materials and transition metal oxides. The cooling method we have developed is applicable to any species, including fermionic atoms. Our results are available in Ref. [3]
optical lattices; non-equilibrium; ultracold atoms; dynamics; atomic physics; quantum quench; Kibble-Zurek; band decay; cooling; strongly correlated
Fri, 17 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/880772015-07-17T00:00:00ZChen, DavidGluon polarization in the proton: constraints at low x from the measurement of the double longitudinal spin asymmetry for forward-rapidity hadrons with the PHENIX detector at RHIC
http://hdl.handle.net/2142/88073
Gluon polarization in the proton: constraints at low x from the measurement of the double longitudinal spin asymmetry for forward-rapidity hadrons with the PHENIX detector at RHIC
McKinney, Cameron Palmer
In the 1980s, polarized deep inelastic lepton-nucleon scattering experiments
revealed that only about a third of the proton's spin of $\frac{1}{2}\hbar$
is carried by the quarks and antiquarks, leaving physicists with the
puzzle of how to account for the remaining spin. As gluons carry roughly
50\% of the proton's momentum, it seemed most logical to look to the
gluon spin as another significant contributor. However, lepton-nucleon
scattering experiments only access the gluon helicity distribution,
$\Delta g$, through effects on the quark distributions via scaling
violations. Constraining $\Delta g$ through scaling violations requires
experiments that together cover a large range of $Q^{2}$. Such experiments
had been carried out with unpolarized beams, leaving $g(x)$ (the
unpolarized gluon distribution) relatively well-known, but the polarized
experiments have only thus far provided weak constraints on $\Delta g$
in a limited momentum fraction range.
With the commissioning in 2000 of the Relativistic Heavy Ion Collider,
the first polarized proton-proton ($pp$) collider, and the first
polarized $pp$ running in 2002, the gluon distributions could be
accessed directly by studying quark-gluon and gluon-gluon interactions.
In 2009, data from measurements of double longitudinal spin asymmetries,
$A_{LL},$ at the STAR and PHENIX experiments through 2006 were included
in a QCD global analysis performed by Daniel de Florian, Rodolfo Sassot,
Marco Stratmann, and Werner Vogelsang (DSSV), yielding the first direct
constraints on the gluon helicity. The DSSV group found that the contribution
of the gluon spin to the proton spin was consistent with zero, but
the data provided by PHENIX and STAR was all at mid-rapidity, meaning
$\Delta g$ was constrained by data only a range in $x$ from 0.05
to 0.2, leaving out helicity contributions from the huge number of
low-$x$ gluons. A more recent analysis by DSSV from 2014 including
RHIC data through 2009 for the first time points to significant gluon
polarization at intermediate momentum fractions, meaning gluon polarization
measurements may be more interesting than anticipated, especially
at momentum fractions where no constraints exist as of yet.
A forward detector upgrade in PHENIX, the Muon Piston Calorimeter
(MPC), was designed with the purpose of extending the sensitivity
to $\Delta g$ to lower $x$. Monte Carlo simulations indicate that
measurements of hadrons in the MPC's pseudorapidity of range $3.1<\eta<3.9$
probe asymmetric collisions between high-$x$ quarks and low-$x$
gluons, with the $x$ of the gluons reaching below 0.01 at a collision
energy $\sqrt{s}=500\,GeV$. We access $\Delta g$ through measurements
of $A_{LL}$ for electromagnetic clusters in the MPC; this thesis
details the measurement from the Run 11 (2011) data set at $\sqrt{s}=500\,GeV$.
We find $A_{LL}\approx0$, but the statistical uncertainties from
this measurement mean we likely cannot resolve the small expected
asymmetries. However, improved techniques for determining the relative
luminosity between bunch crossings with different helicity configurations
will allow data from a much larger data set in Run 13 to be most impactful
in constraining $\Delta g,$ whereas previous measurements of $A_{LL}$
have had difficulties limiting the systematic uncertainty from relative
luminosity.
In this thesis, we begin by presenting an overview of the physics
motivation for this experiment. Then, we discuss the experimental
apparatus at RHIC and PHENIX, with a focus on those systems integral
to our analysis. The analysis sections of the thesis cover calibration
of the Muon Piston Calorimeter, a careful examination of the relative
luminosity systematic uncertainty, and the process of obtaining a
final physics result.
PHENIX; proton spin; gluon polarization; double spin asymmetry; Delta G
Fri, 17 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/880732015-07-17T00:00:00ZMcKinney, Cameron PalmerTransport and disorder-induced localization of ultracold Fermi gases
http://hdl.handle.net/2142/88039
Transport and disorder-induced localization of ultracold Fermi gases
McGehee, William R
We experimentally study localization and dynamics of ultracold fermions in speckle and optical lattice potentials to explore Anderson localization, many-body localization, and relaxation dynamics in strongly correlated systems. Anderson localization is probed by releasing non-interacting, spin-polarized gases into three dimensional, anisotropic disordered potentials produced from optical speckle. A fraction of the atoms are localized by the disorder, and a mobility edge is found separating localized from extended states. The length scale of the speckle is varied, and the localized state is found to scale linearly with the geometric mean of the speckle autocorrelation length. We realize the Fermi Hubbard model by loading atoms in a cubic optical lattice. Non-equilibrium momentum distributions are created via Raman transitions, and the excitation relaxation rate is measured in the lattice. Transport experiments were performed in a disordered optical lattice to explore the disordered Hubbard model. These experiments reveal localization in the presence of strong interactions and an interaction driven metal-to-insulator transition. The localized state is found to be insensitive to a doubling in the temperature of the gas and is consistent with predictions of many-body localization.
Anderson Localization; Many-Body Localization; Optical Speckle; Optical Lattice; Ultracold Atoms; Disordered Transport; Strongly-Interacting Materials; Hubbard Model; Fermi-Hubbard Model; Fermi Gas
Tue, 14 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/880392015-07-14T00:00:00ZMcGehee, William RTerahertz oscillations of hot electrons in graphene
http://hdl.handle.net/2142/88002
Terahertz oscillations of hot electrons in graphene
Sekwao, Samwel Kedmon
Once a uniform electric field is turned on in graphene, carriers accelerate ballistically until they are scattered
by optic phonons and the process repeats itself. In this dissertation, I will show that the oscillatory nature
of the motion of the carrier distribution function manifests in damped oscillations of carrier drift velocity
and average energy. In appropriate fields, the frequency of such oscillations can be in the terahertz (THz)
range. The randomizing nature of optical phonon scattering on graphene’s linear band structure further
limits terahertz observation to a range of sample lengths.
I will also show that when an ac field is superimposed onto the appropriate dc field, hot carriers in
graphene undergo an anomalous parametric resonance. Such resonance occurs at about half the frequency
ωF = 2πeF/~ωOP , where 2π/ωF is the time taken for carriers to accelerate ballistically to the optic phonon
energy ~ωOP in a dc field F. For weak elastic scattering, the phase difference between the current and the
ac field has a nonzero minimum at resonance. Dephasing increases with ac frequency for stronger elastic
scattering. The overall effect could also be seen in long-range spatially periodic potentials under steady state
conditions.
This dissertation also shows that the soft parametric resonance (SPR) at ω = ηωF is temperature
independent, and the resonance factor η ∼ 0.56 is weakly dependent on the dc field Fo. This ensures
tunability of resonant frequencies in the terahertz range by varying Fo. A small signal analysis (SSA) of the
time-dependent Boltzmann transport equation (BTE) reveals a second resonance peak at η ∼ 1. This peak
is prevalent at temperatures T ≤ 77 K, and appears as a weak shoulder at T = 300 K.
Finally, this dissertation shows that in graphene, the motion of carriers under the influence of temporarily
and spatially modulated scattering is characterized by sharp resonances. Such resonances occur when the
period of the ac field applied equals the time taken by the quasi-ballistic carriers to travel a spatial distance
corresponding to the wavelength of the field. I will also show that such scattering can be realized on graphene
sheets on periodically spaced gates energized by an a-c bias. Appropriate fields and gate separation will
result in high Q-factor resonances in the THz range. The resonant frequencies are tunable with the gate
separation, and higher harmonics with large Q-factors can also be achieved.
Graphene Terahertz
Fri, 10 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/880022015-07-10T00:00:00ZSekwao, Samwel KedmonA search for the ttH (H → bb) channel at the Large Hadron Collider with the ATLAS detector using a matrix element method
http://hdl.handle.net/2142/88000
A search for the ttH (H → bb) channel at the Large Hadron Collider with the ATLAS detector using a matrix element method
Basye, Austin Thomas
A matrix element method analysis of the Standard Model Higgs boson, produced in association with two top quarks decaying to the lepton-plus-jets channel is presented. Based on 20.3 fb−1 of √s=8 TeV data, produced at the Large Hadron Collider and collected by the ATLAS detector, this analysis utilizes multiple advanced techniques to search for tt ̄H signatures with a 125 GeV Higgs boson decaying to two b-quarks. After categorizing selected events based on their jet and b-tag multiplicities, signal rich regions are analyzed using the matrix element method. Resulting variables are then propagated to two parallel multivariate analyses utilizing Neural Networks and Boosted Decision Trees respectively. As no significant excess is found, an observed (expected) limit of 3.4 (2.2) times the Standard Model cross-section is determined at 95% confidence, using the CLs method, for the Neural Network analysis. For the Boosted Decision Tree analysis, an observed (expected) limit of 5.2 (2.7) times the Standard Model cross-section is determined at 95% confidence, using the CLs method. Corresponding unconstrained fits of the Higgs boson signal strength to the observed data result in the measured signal cross-section to Standard Model cross-section prediction of μ = 1.2 ± 1.3(total) ± 0.7(stat.) for the Neural Network analysis, and μ = 2.9 ± 1.4(total) ± 0.8(stat.) for the Boosted Decision Tree analysis.
Higgs Boson; Large Hadron Collider (LHC); A Toroidal LHC Apparatus (ATLAS); 8 TeV; ttH; H to bb; Matrix Element Method; Neural Network; Boosted Decision Tree; Standard Model
Tue, 07 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/880002015-07-07T00:00:00ZBasye, Austin ThomasTopological semimetals and nodal superconductors
http://hdl.handle.net/2142/87989
Topological semimetals and nodal superconductors
Chang, Po-Yao
Besides topological band insulators, which have a full bulk gap, there are also gapless phases of matter that belong to the broad class of topological materials, such as topological semimetals and nodal superconductors. We systematically study these gapless topological phases described by the Bloch and Bogoliubov-de Gennes Hamiltonians. We discuss a generalized bulk-boundary correspondence, which relates the topological properties in the bulk of gapless topological phases and the protected zero-energy states at the boundary. We study examples of gapless topological phases, focusing in particular on nodal superconductors, such as nodal noncentrosymmetric superconductors (NCSs). We compute the surface density of states of nodal NCSs and interpret experimental measurements of surface states. In addition, we investigate Majorana vortex-bound states in both nodal and fully gapped NCSs using numerical and analytical methods. We show that different topological properties of the bulk Bogoliubov-quasiparticle wave functions reflect themselves in different types of zero-energy vortex-bound states. In particular, in the case of NCSs with tetragonal point-group symmetry, we find that the stability of these Majorana zero modes is guaranteed by a combination of reflection, time-reversal, and particle-hole symmetries. Finally, by using K-theory arguments and a dimensional reduction procedure from higher-dimensional topological insulators and superconductors, we derive a classification of topologically stable Fermi surfaces in semimetals and nodal lines in superconductors.
Topology; Topological semimetals; Nodal superconductors; Entanglement spectrum; Topological insulators; Non-centrosymmetric superconductors; K-theory; Classificaltions
Mon, 06 Jul 2015 00:00:00 GMThttp://hdl.handle.net/2142/879892015-07-06T00:00:00ZChang, Po-YaoPair density wave superconducting states and statistical mechanics of dimers
http://hdl.handle.net/2142/87983
Pair density wave superconducting states and statistical mechanics of dimers
Soto Garrido, Rodrigo Andres
The following thesis is divided in two main parts. Chapters 2, 3 and 4 are devoted to the study of the so called pair-density-wave (PDW) superconducting state and some of its connections to electronic liquid crystal (ELC) phases, its topological aspects in a one dimensional model and its appearance in a quasi-one dimensional system. On the other hand, chapter 5 is focused on the investigation of the classical statistical mechanics properties of dimers, in particular, the dimer model on the Aztec diamond graph and its relation with the octahedron equation.
In chapter 2 we present a theory of superconducting states where the Cooper pairs have a nonzero center-of-mass momentum, inhomogeneous superconducting states known as a pair-density-waves (PDWs) states. We show that in a system of spin-1/2 fermions in two dimensions in an electronic nematic spin-triplet phase where rotational symmetry is broken in both real and spin space PDW phases arise naturally in a theory that can be analysed using controlled approximations. We show that several superfluid phases that may arise in
this phase can be treated within a controlled BCS mean field theory, with the strength of the spin-triplet nematic order parameter playing the role of the small parameter of this theory. We find that in a spin-triplet nematic phase, in addition to a triplet p-wave and spin-singlet d-wave (or s depending on the nematic phase) uniform superconducting states, it is also possible to have a d-wave (or s) PDW superconductor. The PDW phases found here can be either unidirectional, bidirectional, or tridirectional depending on the spin-triplet nematic phase and which superconducting channel is dominant. In addition, a triple-helix state is found in a particular channel. We show that these PDW phases are present in the weak-coupling limit, in contrast to the usual Fulde-Ferrell-Larkin-Ovchinnikov phases, which require strong coupling physics in addition to a large magnetic field (and often both).
In chapter 3 we show that the pair-density-wave (PDW) superconducting state emergent in extended Heisenberg-Hubbard models in two-leg ladders is topological in the presence of an Ising spin symmetry and supports a Majorana zero mode (MZM) at an open boundary and at a junction with a uniform d-wave one-dimensional superconductor. Similarly to a conventional finite-momentum paired state, the order parameter of the PDW state is a charge-2e field with finite momentum. However, the order parameter here is a quartic electron operator and conventional mean-field theory cannot be applied to study this state. We use bosonization to show that the 1D PDW state has a MZM at a boundary. This superconducting state is an exotic topological phase supporting Majorana fermions with finite-momentum pairing fields and charge-4e superconductivity.
In chapter 4 we provide a quasi-one-dimensional model which can support a PDW state. The model consists of an array of strongly-interacting one-dimensional systems, where the one-dimensional systems are coupled to each other by local interactions.Within the interchain mean-field theory (MFT), we find several SC states from the model, including a conventional uniform SC state, PDW SC state, and a coexisting phase of the uniform SC and PDW states. In this quasi-1D regime we can treat the strong correlation physics essentially exactly using bosonization methods and the crossover to the 2D system by means of interchain MFT. The resulting critical temperatures of the SC phases generically exhibit a power-law scaling with the coupling constants of the array, instead of the essential singularity found in weak-coupling BCS-type theories. Electronic excitations with an open Fermi surface, which emerge from the electronic Luttinger liquid systems below their crossover temperature to the Fermi liquid, are then coupled to the SC order parameters via the proximity effect. From the Fermi surface thus coupled to the SC order parameters, we calculate the quasiparticle spectrum in detail. We show that the quasiparticle spectrum can be fully gapped or nodal in the uniform SC phase and also in the coexisting phase of the uniform SC and PDW parameters. In the pure PDW state, the excitation spectrum has a reconstructed Fermi surface in the form of Fermi pockets of Bogoliubov quasiparticles.
In chapter 5 we study the octahedron relation (also known as the A∞ T-system), obeyed in particular by the partition function for dimer coverings of the Aztec Diamond graph. For a suitable class of doubly periodic initial conditions, we find exact solutions with a particularly simple factorized form. For these, we show that the density function that measures the average dimer occupation of a face of the Aztec graph, obeys a system of linear recursion relations with periodic coefficients. This allows us to explore the thermodynamic limit of the corresponding dimer models and to derive exact “arctic” curves separating the various phases of the system.
High Temperature Superconductivity; Pair Density Wave; Arctic Curves; Aztec Diamond; Topological Superconductors
Tue, 30 Jun 2015 00:00:00 GMThttp://hdl.handle.net/2142/879832015-06-30T00:00:00ZSoto Garrido, Rodrigo AndresSome effects of dimensionality and defects on superconductivity
http://hdl.handle.net/2142/87980
Some effects of dimensionality and defects on superconductivity
Yu, Jitong
This thesis reports some theoretical studies of superconductivity with reduced dimensions. After an intro- duction to the physics of superconductivity with reduced dimensions, we reports our studies in three main topics in this thesis. In Chapter 2, the resistance of superconducting thin wires with finite length is derived in regimes where the LAMH theory fails.
In Chapter 3, we consider the effect of planar defects on the superconductivity of Sr2RuO4 thin films. We find that while parallel planar defects does not decrease the the transition temperature of superconductivity, defects that are perpendicular with each other are able to suppress the superconductivity.
In Chapter 4, we study the interaction between vortices and interface between two perpendicular anisotropic superconductors. The interface is found to be able to trap vortices and the trapping potential is calculated. This mechanism can be utilized to produce wires with larger critical current density.
superconductor; superconducting; dimensionality; defect; nanowire; Langer–Ambegaokar–McCumber–Halperin (LAMH); resistance; planar defects; Sr2RuO4; vortex pinning; critical current
Tue, 30 Jun 2015 00:00:00 GMThttp://hdl.handle.net/2142/879802015-06-30T00:00:00ZYu, JitongMastery-style exercises in physics
http://hdl.handle.net/2142/87963
Mastery-style exercises in physics
Schroeder, Noah D
Mastery learning employs repeated cycles of instructional support and formative assessment to help students achieve desired skills. Instructional objectives are broken into small pieces, and students master those pieces in successive order by performing to a set standard on an assessment for each objective. If a student cannot master an objective, instructional support is provided, and the student is reassessed. Mastery learning has been proved effective in many subject areas, but comparatively little research has been done on applying it in physics instruction. This dissertation details the path taken that culminated in the use of mastery-inspired exercises to teach students basic skills in introductory physics courses.
The path that led to our choice of mastery began with an attempt to provide students with extra practice and formative assessment through weekly practice tests with corresponding solutions, with the goal of helping them better prepare for summative exams in an introductory physics course. No effect was seen, and participation was very low. Investigating how students learn from solutions revealed that they are poor evaluators of their understanding of provided solutions and struggle to retain the skills taught in those solutions. In a follow-up clinical experiment that provided students with solutions, required them to recall the solutions from memory, and re-presented the solutions for restudy, students showed strong retention as well as the ability to transfer information from the solutions to new situations. These results inspired the formal use of mastery learning as an instructional paradigm due to its requirement that students repeatedly recall information from solutions and apply it to new situations.
Mastery-style exercises were first created and tested in clinical trials, followed by two in-course implementations. In the clinical trials, students completed a set of questions on a particular skill, and if they failed to master that skill, they were given support in the form of narrated animated solution videos followed by a new version of the question set. On mastering a skill, students moved on to the next skill level. Students mastered all provided skill levels and then took a post-test. Those clinical trials demonstrated that students can use provided solutions to quickly progress through successive levels of mastery exercises and that mastery-style exercises had a larger impact on the post-test than traditional multi-try immediate feedback homework exercises. Following these strong results, mastery-style exercises were implemented over an entire semester in an introductory course, replacing the existing homework. Participation was much poorer than in the clinical experiments due to frustration with the difficulty of the provided exercises. As a result the implementation had a comparatively small impact on student performance. Frustrated students circumvented the system by ignoring provided solutions and skipping assessments, choosing instead to cycle through the provided versions until they could reattempt an already seen version of an assessment. A follow-up implementation covering a single week had a larger impact on a quiz, yet students were still frustrated with the exercises and displayed behaviors similar to those seen in the semester-long implementation.
Moving forward, frustration must be overcome to return participation to levels seen in the clinical trials. A preliminary development mode is suggested to ensure proper calibration of difficulty to student skills. Other changes involving how the mechanics of the system work as well as how its benefits are communicated to students are also suggested. If frustration is overcome and participation increases, the incredible potential of mastery-inspired exercises can be realized. Mastery is a powerful addition to physics instruction.
Mastery; Physics; Physics Education; Science Technology Engineering Mathematics (STEM) Education
Tue, 16 Jun 2015 00:00:00 GMThttp://hdl.handle.net/2142/879632015-06-16T00:00:00ZSchroeder, Noah D